Thread-cutting device for sewing-machines.



R. L. LYONS.

THREAD CUTTING DEVICE FOR SEWING MACHINES.

APPLICATION FILED DEO.23,1907.

Patented Marl26,1912.

2 SHEETS-SHEET 1.

64 RM qhk m R. L. LYON S. THREAD CUTTING DEVICE FOR SEWING MACHINES.

APPLICATION FILED 10110.23, 1907.

Patented Mar. 26, 1912.

2 QHBETB-SHEET 2.

ivvamiazw am m UNITED STATES PATENT OFFICE. ROBERT JiaYdNS, 013 BOSTON, MASACHUSETTS, AS SIGNOR TO HIMSELF, CHARLES J. SIIBBALD, OF ROCHESTER, NEW YORK.

THREAD-CUTTING DEVICE FOR SEWTNG-MACHINES.

Specification of Letters Patent.

Patented Mar. 26, 1912.

To vall whom it may concern Be it known thatI, ROBERT L. Lyons, of Boston, in the county of Suffolk and State of'Massachusetts, have invented certain new and useful Improvements in Thread-Cutting Devices for Sewing-Machines; and I hereby declare that the following is a full,

clear, and exact description of the same, reference being had to the accompanying drawings, forming part of this specification.

- This invention has reference to improvements in thread cutting devlces for sew ng machines and partlcularly to such devices designed to cut the needle thread. 15

struct a needle-thread cutting device that a One object of this invention is to so contional resistance of the tension and drawn laterally between the work and the needle and the frictional contact of the tension may then be brought to act on the thread to resist its drawing 'out.

Other objects: of the invention will appear from the following description of the mechanism.

The invention consists in the peculiar construction of the thread cutter and in the means for operating the same.

The invention also consists in the peculiar means for engaging the thread between the needle and the work and moving said thread laterally} The invention also consists in the means for engaging the needle thread to draw the same laterally combined with means for releasing the tension and for subsequently permitting the tension to reengage said thread. '45

novel features of construction and combina- The invention also consists in such other tion of parts as shall hereinafter be more fully described and pointed out in the claims. Figure 1, represents an end view of portions of a sewing machine of ordinary construction illustrating this invention parts of the same being shown in section. F ig. 2, represents a cross sectional view taken on line 2-2, Fig; 1 looking downward with the parts shown as in position when the presser foot is depressed. Fig. 3, represents a sumlar view with the parts positioned as when the pre'sser foot is raised. Fig. 4, is adiagrammatic view showing approximately the relative positions of the lateral moving thread carrier and the thread cutter with respect to the needle and the work.

Similar numbers of reference corresponding parts throughout.

As shown in the drawings in its preferred form, 5 indicates the bed plate of any well known sewing machine which has the head 6 furnished with the usual needle bar 7, ;t he presser foot rod 8 slidably mounted in said head, and the usual disk tension device 9, mounted on said head, through which the needle thread a is led toward the needle. Pivotally mounted on the head 6 is the lever 10 which is connected with the presser foot rod 8 and is designed to slide said rod u-pdesignate ward when the free end of said lever is depressed. At the upper part of the head 6 is the bracket 11 in which is mounted the rock shaft 12 having the arm 13, which is connected'by the rod 14 with the lever 10, and the beveled edge blade 15 designed to swing between the disks of the tension device 9 to separate said'disks and release theneedle thread and thereafter to swing from between said disks and permit ofthelr reaction a ainst the said thread. Slidably mounted in a perforation of the bed plate 5 and connected with the lever 10 is the spring retracted rod 16 furnished with the block 17 which is adjustably secured on said rod and has the cam 18. The presser foot is, in this particular instance, the button clamp 19 which is pivota-lly connected with the rod 8 and also with the base 20 which is of the usual construction known in button sewing machines. Pivotally mounted on the button clamp 19 is the arm 21 having the cam 22 andthe extension 23, having the adjustable thread engaging finger 24 while, rearwardly of its pivot, said arm 21 has the member25 furnished with the bearing 26. A retracting spring 27 is connected with said member 25 and with the pin 28 fixed on the button clamp whereby the retractive strain of said spring tends constantly to draw said member 25 toward the stop pin 29 fixed on the but-ton clamp which pin limits the movement of said member. On the button clamp 19 is also pivoted the cutter arm 30 having l at forward end, the cutting blade 31 and vfurnished at its rear portion with the member 32 adapted to be engaged by the cam 22 of the arm 21 and moved, by the movement ofthe latter, against the action of the spring 33 connected to the member 32 and to the pin 34 on the button clamp which pin acts as a stop for said member to limit its retractive movement.

After the completion of the group of stitches which secures the button 6 with the cloth 0 the needle 03 rises to the position shown in-Figs. 1 and 4 and the needle thread a extends between the eye of the needle-and the hole of the button through which the needle has last passed. To facilitate the withdrawal of the Work from the machine the free end of the button clamp 19 is now preferably raised, by the depression of the free end of the lever 10, and the resultant upward movement of the rod 8 connected with the button clamp. As the lever 10 swings downward the blade 15, actuated through. the .movementof said lever, swings and swings .said member and its arm 21 upward and enters between the leaves or disks of the tension device 9 thereby separatingsaid disks and relieving the tension on the thread. Approximately as the tensionis released the cam 18, of the rod 16, engages the bearlng 26 of' -the member againstthe action of the spring 27 and in a direction whereby the finger 24 swings between the needle and the work, from the position shown in full lines in Fig. 4 to the position indicated in dotted lines therein,

andcarries the loosened needle thread laterally as indicated'in said figure. At or near this extreme limit of movement of the finger 24 the blade 15 swings from between the disks of the tension device 9 which are again permitted to exert tensio'mon the thread. During the thread positioning movement of the arm 21 the cam 22 thereof engages the end portion of the member 32 of the cutter arm 30 and effects the swinga ing of the same to swing the cutting blade 31 to the position shown in Figs. 3 and 4';

the work is now drawn from the button clamp and the tightened thread is drawn across the edge of the blade 31 and is cut.

\Vhen the free end of the .lever 10 moves upward the several parts are retracted to the inoperative positions.

It is of course evident that the cutting I blade may, in .its forward movement, be

brought against the needle threadpto-s jever,

said thread before the work isi'drawn from the machine but I prefer to eflect' such cutting by drawingthe thread against the edge of said cutter as the work is drawn from the machine. It is also evident that the means for moving the thread laterally may chines comprising a'button clamp pivotally mounted means formovin the same, a cutter arm pivotally mounte on said button clamp and having a blade, a thread engaging-arm pivotally mounted on said button clamp and adapted to engage and move the cutter arm, and means for effecting the movement of said thread engaging arm.

2. A thread cutting device for sewing machines comprising a thread engaging arm and a threadcutter movably mounted to swing in opposite directions, means for swinging the same, a thread tension,-and

means'for releasing said tension during the swinging of the thread engaging arm.

3. A thread cutter for sewing machinescomprising a button clamp pivotally mounted means for efiecting the movement thereof, a" thread cutter arm pivoted on said button clamp and having a cutter, a thread engaging arm pivoted on the but-ton clamp and designed 'to engage and 'move said cutter arm, and means for effecting the movement of the thread engaging arm during the upward movement of the button clamp.

.4. A thread cutter for sewing machines comprising a button clamp pivotally mounted, means for moving the same, a thread engaging arm pivotally mounted on the button clamp, means actuated by the but-ton clamp moving means for moving said arm, a tension device, and means connected with the buttonclam moving means for releasing said tension uring the movement of the thread engaging arm.

. ROBERT L. LYONS. Witnesses H. J.- Mame, M,. M. HARRINGTON. z :1

Copies of this patent maybe obtained for five cents .each, by addressing the Commissioner Washington, D. 0.

6f i atents, 

